Get the list of all different font sizes on a page.

getAllFontSizes.js

//requires jQuery & lodash

(function getAllFontSizes (fontSizes) {
  $('*').each(function (i, n, s) { s = getComputedStyle(n)['font-size']; (s !== '0px') && fontSizes.push(s) });
  console.log(_.chain(fontSizes).uniq().sortBy(function (v) { return parseInt(v, 10); }).join(', ').value());
}([]));